The present study followed 156 Finnish children (M[subscript age] = 7.25 years) during the first grade of primary school to examine to what extent parent- and teacher-rated temperament impacts children's math and reading skill development during the first grade, and the extent to which this impact would be mediated by teachers' interaction styles with the children. The results showed that the impact of children's low task orientation and negative emotionality on their math skill development was mediated via teachers' behavioral control and, among girls, also by psychological control. The negative impact of children's inhibition on math skill development, in turn, was not mediated via teachers' interaction styles. Temperament did not predict the children's reading skill development during first grade.